One Thing I Didn't Get to Do
by PFTones3482
Summary: Star and Marco graduate in a week, and Star comes into Marco's room late one night while he's studying to tell him that there was one last thing she wanted to do before she left Earth. M for a reason, written because I know there are definitely people who want some more Starco. One shot.


**Note: Star and Marco are both 18 in this story.**

 **I'm sorry, there needed to be some better M rated stories, one where Marco ISN'T controlling and snarky, where Star isn't clueless about how sex works (because COME ON why would she be?), and where there's a decent story behind everything.**

 **I don't own Star vs. the Forces of Evil.**

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GENERAL POV

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"Star? Its almost one am, what's wrong?" Marco asked softly, looking curiously at the girl over his history text book.

The 18 year old bit her lip and glanced down, twisting her nightshirt in her hands. "Marco….we graduate in two weeks."

He hesitated and set the book down on his desk, pushing back his chair. "I know, why do you think I'm studying? Finals are coming up on Monday."

Star nodded and looked up at him nervously. "Marco I…I leave for Mewni right after we graduate. Like right after."

Marco felt his heart thud loudly in his chest and he stood up, crossing the room and gripping Star's shoulders. "I know. I know."

Tears welled up in her eyes and she buried her face in his chest. "I don't want to go, Marco. I don't want to leave earth, don't want to leave YOU."

Marco smiled tenderly and wrapped his arms around her, running his fingers through her hair. "I know, Star. I don't want you to go either. But it's your duty as queen."

Star pushed back from him and scowled, pouting her lip out in a cute way that made Marco's throat go dry. "Maybe I don't want to be queen. Maybe I want to stay here, with you."

Marco swallowed and brushed her hair behind her ears. "Star, I would love that," he whispered. "But you know it's not possible."

His hand remained on her cheek and she leaned against it, her eyes sad. "I know," she finally mumbled. "Marco…there was one thing I never got to do on earth that I really wanted to do."

Marco stepped back immediately, a smile on his face. "Name it, Princess Butterfly. Go to the moon? Cross a desert? Steal the Mona Lisa? Okay…maybe not that. But whatever it is, we can do it before you go."

Star giggled and shook her head. "Nothing that drastic, Diaz, I promise. Though the Mona Lisa would make a nice painting for my wall in Mewni."

Marco gave her a teasing scowl and she smiled, pressing his shoulder lightly. "No, the one thing I never got to do was right here in town."

He frowned, tilting his head. "Really? But we've been like everywhere in town."

Star bit her lip and fiddled with a piece of hair as she stepped closer to Marco, their bodies nearly touching. His pulse sped up and he gulped. "S-Star?"

One look at her intense gaze and he knew what she meant. His lips softened into a smile and he gently slid an arm around her waist, drawing her closer and leaning down so that their foreheads touched.

"You," Star breathed, her voice low as she wrapped her arms around his neck. "I never got you."

He pressed his lips to hers tenderly and she sank into his grasp, her fingers teasing at the fine hair on the back of his neck. He tugged her tight against him with one hand and slid the other up to caress her cheek.

"Marco," she murmured against his mouth. His heart rate jumped and he pressed his lips to her jaw before roving the kisses down her neck. Star gasped and tugged at his hair, arching her body against his.

Marco shuddered and brought his lips back to her mouth, sliding his tongue against her and deepening the kiss as much as possible.

"Star," he groaned. "I…I wanted you too. So much."

She broke the kiss and leaned their foreheads together, panting. Her eyes sparkled and she pressed a kiss to his mole, a smile on her lips. "We got all night, Diaz."

The implications of her words were not lost on Marco and he flushed deeply. Nevertheless, he hit the overhead light so that only the glow in the dark constellations on his walls lit the room and he brought his mouth back to Star's skin, nipping at it and sucking at it as her hands dug deeper and deeper in his hair.

They stumbled backwards until the back of Star's legs hit Marco's bed, and then he slowly leaned her back until they were laying side by side on his comforter.

Star rolled so that she was facing him and tucked one of her legs over his hips, drawing him closer and sending a very pleasing jolt through Marco's body. He groaned and pulled her flush against him, their hands tugging at each others clothing until finally they were both shirtless.

Marco swallowed hard, his pants getting visibly tighter in the dim light of the room. Star smiled at him hesitantly, her blonde hair tumbling all over the bed and caressing her already bare breasts gently.

With a soft finger, she brought his hand up to her chest and settled his palm on her, making both of them shiver.

He rubbed a rough thumb, hard from six years of constant karate, over her nipple and Star groaned, yanking him forwards and pressing their lips together.

Marco brought his other hand up and rolled so that Star was on top of him. He palmed both breasts and began tweaking at her already firm nipples, making the young woman gasp and writhe on top of him.

Her movement caused unbearable friction to Marco's lower half and he could barely bite back his moans of pleasure. He slid down her torso and wrapped his mouth around her left nipple, continuing to stroke and pinch at the other one as he sucked the first.

Star's breath came in pants and she fumbled to remove her pajama bottoms. Marco halted his work on her chest and followed suit, slipping out of his tight jeans and tossing them to the floor with the rest of their clothes.

They were left now in only their underwear and Star smirked a little at the tent that had formed in Marco's boxers. He hissed as she stroked a finger around the top of it and she grinned, starting to pull on his waistband.

"Wait," Marco gasped, wrapping his fingers around her wrist and staring her in the eyes, his gaze intense in the darkness. "Star, are you sure?"

She smiled and leaned over, kissing his neck and letting her tongue drag across the skin. "As long as you're sure," she whispered into his ear.

Marco pulled the boxers down himself, revealing his erection to his longtime friend. She studied it for a moment, a little wary, and Marco gently tugged her in for a kiss. "Whatever you want," he murmured, his heart pounding in his chest.

She slid her hands down to his hard on and wrapped her fingers around him delicately, making Marco groan. "I want you," she finally said, giving him a couple of tugs.

He wrapped his hands around her waist and pulled her on top of him, slipping his fingers under the fabric of her underwear and stroking just at the curve of her thighs.

Star gasped and reached down, intent on pulling her underwear off. Marco, always one step ahead, slid the panties down her legs and let her kick them off before bringing his hands back up and grabbing her butt, squeezing her cheeks lightly.

The woman growled and thrust her hips at him, their waists colliding and making both of them moan. Marco brought his hands sliding down her stomach again and teased at her opening, causing Star to arch against him.

"Dammit, Marco," she grumbled, running her lips down his neck and suckling at his collarbone.

She crawled down his body, trailing kisses, and planted one directly on his erection before slithering her tongue around the very tip. Marco groaned and thrust upwards, but Star backed up quickly and settled down on Marco's thighs, running a finger up and down his throbbing length.

Unable to take it, Marco grabbed the princesses arms and flipped her so that he was hovering over her, their eyes meeting in the dim lighting.

Star giggled softly and Marco relaxed a little, a grin on his cheeks. "Sorry," he apologized, tracing a hand down her side. "Star, I don't have protection."

She pressed a kiss to his lips. "People on Mewni can't get pregnant until the age of 21. It's genetically impossible. And we also can't contract earth diseases."

Marco felt his heart flutter in his chest and he leaned down, pressing kisses to her lips, her cheeks, her nose, her breasts, her neck, and her shoulders. "All right. Just so you know, you're my first."

She smiled up at him, her eyes shining. "You're mine. And that's all that matters."

Marco blushed and then crawled down, pressing his lips to the inside of her thighs and up against her center, making Star gasp and writhe underneath him.

He moved back up to her torso and reached down, aligning himself with her. "Ready?"

She smiled up at him and spread her legs, making the young man grin. He kissed her nose tenderly and then slid into her slowly, his brain running a mile a second as his sensors overwhelmed him.

Star's fingers dug into his forearms and sweat beaded her forehead. Marco stopped for a moment and rested their bodies together, letting her relax.

"You okay?" he asked after a moment, his voice strained.

She nodded and gave him a loving smile and he contuned pushing in until their hips were connected. After giving Star a second to adjust, he pulled back and thrust into her again.

Both young adults moaned and Star grabbed at the sheets as Marco started pushing in and out and in and out, their sweat mingling and hearts racing. Star began thrusting her hips up every time she felt him pull back, creating more friction between the two.

Marco kept a firm grip on Star's hips and she wrapped her legs tightly around him, pulling his throbbing dick closer to her.

Panting, Marco was able to feel the pit of warmth building up in his stomach, and by the way his name kept tumbling from Star's lips, he knew she was close too.

He brought his hand down and ran his thumb blindy over her clitoris a few times. Star's body shook under him and he could feel her walls clenching around him, ready to let go.

He frantically thrusted into her and came only seconds after she did. Both of them were groaning so loudly that Marco was afraid his parents might have heard, but he didn't really care.

She went limp under him, her chest heaving, and Marco pulled out of her and crawled up to lie beside her.

He reached out and drew her to him, entwining their legs together and letting her rest her head on his chest.

"I love you, Star," Marco finally admitted, shutting his eyes. "I was always so afraid to tell you because I knew you would leave."

A tiny giggle rose from the depth of his chest and he glanced down to find Star grinning up at him widely. She rubbed a leg against his and kissed his chin.

"I love you too, Marco. And I'm not leaving."

Marco furrowed his eyebrows. "Huh?"

Star leaned her head on his shoulder and shivered a little. Marco pulled her closer as she spoke. "On Mewni, the princess is only allowed to have sex with whoever she marries. Once you've had sex with them, you have to marry them. They always make you wait until the arranged wedding night."

Marco scowled. "That's a really stupid law," he grumbled.

Star shrugged. "Dad's trying to change it, but Mom is really old fashioned. Anyway, once you've had sex, no other prince is allowed to take you, whether you've had sex with a prince, a commoner…"

She looked up at Marco, a twinkle in her eyes. "…or a really hot guy on earth."

Marco froze and a slow smile slid over his lips. "So…you can't go back to Mewni?"

"Oh I can," Star assured him. "But now no one can marry me. And if another guy even tries, I can have him put to death. I wanted to tell you, but didn't want you to feel like you had to do something you didn't want to do."

Marco pulled her into a tight hug and relished in the fact that she was here, solid, naked with him and never would be with anyone else on Mewni. "I wanted to. I've wanted to for the last like two years, Star."

She nuzzled her head into his shoulder. "Me too."

"You know, I never did finish my studying."

Star giggled and pulled a blanket up over their chests, burrowing into the warmth. "Too bad."

He smiled, pressed a kiss to her scalp, and they fell asleep together comfortably.

And when Mr. and Mrs. Diaz found them like that in the morning? Well, lets just say the adults smirked and didn't say a word.

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 **That's the end. Reviews are welcome.**


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